Functioning principle:

This machine uses what is called a Thermal Wheel or Enthalpy wheel, at it's heart.

After the development costs are recovered the ERV will be released under an MIT license which allows for commercial use.

You can make it yourself, and I recommend purchasing a kit to obtain the non-printable parts efficiently. See the Buy Now page to buy a kit.

Development stage:

*The development of the window mount unit has been largely suspended*. The 5-4 unit is the best, it works and gets ok flow rate, and good efficiency, but it's just a bit noisy, and secondly the gap between the manufacturing cost and resale price is not very large. Clearly that doesn't make for a promising business model. Secondly, people don't seem to be able to understand what it does/why they would want one. That's not good for business. Therefore, I have decided to focus on the wall embed model, which has superior properties on many of these counts.

See the Community page for details.

A test was done on the V4.0 beta model, and the data indicates an excellent 88% efficiency, +/- 4% at a full 21 CFM. You can see a video showing/discussion this test, with commentary, on the YouTube channel.